I've been appalled at the price for anything related to weddings, so I bought some cheap flipflops and dressed them up with lace. The cost was $2.50 for flipflops and $1 for 1 yard of lace. Time spent was less than 30 minutes.

Step 1: Materials

Pair of Flipflops in the correct size, thong-style $2.50 at Old Navy
One yard of lace in a pattern you like, $1 from JoAnn fabrics
Scissors
6 Safety pins
Scalpel or Xacto knife
Opposable thumbs

Step 2: Cut Lace Into Appropriate Length

I used 18 inches of lace on each shoe. You may need more or less depending on how far back the holes are or the size of your shoe.

Step 3: Remove the Thong Part of the Flipflop

Use scissors to cut off the plastic as near to the sole as possible.

Step 4: Push the Attachments Out

In order to empty the holes you will be using, you must remove all the old plastic bits. Push them through to the tread side of the flipflop and try to keep the hole as small as possible.

Step 5: Affix a Safety Pin to the Midpoint of the Lace

To help you thread the lace through the hole, use a safety pin as your needle. It will also be your anchor for the lace. Affix the safety pin to the strongest part of the lace at its midpoint and push the pin through the hole from the top of the shoe to the tread.

Step 6: Rotate the Safety Pin and Secure It

Using your scalpel or xacto knife, cut a tiny tiny slice across the hole on the tread side of the shoe. This will be a niche to hold your safety pin so it doesn't scratch the floor, come undone, or fall back through the hole. Wedge the safety pin into the hole.

Step 7: Admire!

Try on your new flipflop. Collect compliments. When you are done with the laciness, you can recycle the sole or replace the thong with something more durable.